When Leanne and Greg Holdsworth started their coffin-making business Return to Sender they wanted to make a difference. Having seen Leanne's father - who loved timber and had spent his weekends rebuilding old wooden boats - laid to rest in a synthetic casket, they wanted to make coffins with the environment in mind, and also reflect the lives of those who lay within them.

"That's the idea we had nine years ago when we started the business and we were doing that in a very small way. We were looking at ways we could expose our ideas to a much larger group," says Leanne.

Two years ago the couple created a partnership with Davis Funerals, which bought a 50 per cent stake in the business. The company is also looking at new strategies for promoting its products and exploring export markets.

"Eighteen months ago we had 2 per cent of the national coffin market," explains Holdsworth. "We currently have 8 per cent of that market, and by the end of this year we're going to have 12 per cent."

Bill Hale is a Deloitte Private partner and Auckland lead for the Fast 50 index of the country's fastest-growing companies.

Hale says smaller companies that have strong growth understand their competitive advantage. "They find their niche and try to be the best in that. They also love their customers to death and create a loyal following, which means they have a lower cost of sale and get repeat business."

Lesa Davis is managing director of Nitrogenx, an Auckland-based business that sells mainly medical services and equipment and prides itself on its personal approach.

"We're very much a face-to-face company. We visit our clients rather than phoning them or using social media. That has worked well because that helps people to recommend our services to others."

The company is aiming for 15 per cent growth this year and recently held a think-tank to show staff new products and collect ideas about who to sell to and how. "The aim of the think-tank was for staff to learn more about the products and then to throw around ideas about how they might be pitched to our customers, and who else outside our customer base we might target," Davis says.

Coming up in Small Business: Which small businesses are using Instagram to good effect and what are their tips? If you have a story to share, drop me a note:nzhsmallbusiness@gmail.com.